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UNITED STATES DEPARTMENT OF AGRICULTURE 



|H| BULLETIN No. 783 H 

^^"'y^ — '^pi' Contribution from the Bureau of Entomoloev < 



S^.-r^'^^L. 



Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief' 



S\Ji'^^U 



Washington, D. C. 



PROFESSIONAL PAPER 



July 14, 1919 



THE RICE MOTH. 

By F. H. Chittenden, 
<i 

Entomologist In Charge of Truck-Croi) Insect Investigations. 



■'239 



CONTENTS. 



rase. 

Introduction 1 

Nature of injury 1 

Descriptive 2 

The moth 2 

The egg 3 

The larva 3 

The pupa 4 

Distribution 4 



Page. 

Food habits 4 

Reported injuries 5 

Life history 7 

Associated insects 8 

History and literature 9 

Control measures lO 

Summary 13 

Literature cited 14 



INTRODUCTION. 

Among the insect enemies of stored products which have been ob- 
served recently in this country, a small whitish larva or caterpillar 
of the moth Corcyra cephalonica Stainton (PI. I) has attracted atten- 
tion by its injuries. It resembles somewhat the better-known fig 
moth {EjjJiestia cauteUa Walk.). It has not been noted as a pest of 
importance, and has been given no common or English name. As it 
is somewhat widely reported as destructive to stored rice it may 
be called the rice moth. Beginning with October, 1911, complaints 
of damage by this insect were received from a firm manufactur- 
ing chocolate in western Pennsylvania, and a year later from an- 
other manufacturing firm in the same State, but the species was not 
positively identified until 1916. 

NATURE OF INJURY. 

The first correspondent of the Bureau of Entomology who wrote 
of this insect stated that beans of cacao {Theohroma cacao) imported 
from the Tropics were subject to attack by the larva. Apparently it 

104-10!)°— 19 

Nonograpii 



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h 



BULLETIlSr 783, U. S. DEPARTMENT OF AGRICULTURE. 



^^^v 



laid its eggs in the beans, Avhicli are sometimes warehoiisod for several 
months, in the country from which they were shipped. During this 
period of storage additional generations of larvae are hatched which 
destroy large quantities of the cacao beans or render them unfit 
for sale. The rice moths have been found most numerous in the 
older beans and also occur abundantly in cocoa nibs, in cocoa in 
powdered form, in refuse cocoa dust, and in ground cacao shells, 
so that they may be said to feed on any form of the cacao bean from 
the shells to the finished or edible article, cocoa or chocolate in 
powder, in cakes, and in confections, wliether the substance is sweet- 
ened or unsweetened. 

Later moths and lar- 
vae of this species were 
received in rice from 
different sources which 
will be mentioned here- 
after. 

This species works in 
much the same manner 
as do the fig moth {Eph- 
estia cautella TTalk.) 
and the Indian-meal 
moth {Plod la inter- 
punctella Hbn.), form- 
ing a still stronger 
thread than do these re- 

FiG. 1. — Diagram showing wing venation of the rice moth iatCd lOrmS, and mat- 
(After Durrant and Bever- ^ing the iufcstcd ma- 
terial more closely. In- 
deed, this thread or webbing in the case of powdered cocoa becomes 
so dense that in close quarters the moths when emerging are scarcely 
able to make their exit. As a consequence of this and of the further 
fact that the food supply becomes too dry to be eaten, many of the 
larva3 perish. This is true not only under artificial conditions in the 
laboratory but has been noted in manufacturers' storerooms. 

DESCRIPTIVE. 




( Corcyra ccithalon ica) . 
idge.) 



THE MOTH. 



While, as previously stated, the rice moth resembles in certain re- 
spects some of our common moths which breed in stored cereals, 
dried fruits, and similar material, it does not belong to the same lepi- 
dopterous group, being a member of a different family, the Pyrali- 
dae, and subfamily, the Galleriinae, and closely related to a small 
group of moths which are best known as occurring in the combs of 

0. 'Ol: -• 
iUL 25 1919 



THE RICE MOTH. 3 

honeybees and certain species of wasps. Indeed, it is most closely 
related to the lesser bee moth {Achroia g^isclla Fab.), a somewhat 
uncommon species in this country, but well known abroad. 

Corcyra cephalonica is extremely variable in size, specimens which 
were first reared from material received from western Pennsylvania 
being quite small, while individuals from later generations are much 
larger, and in some cases show markings on the forewings more dis- 
tincth^ A moth is shown in Plate I, A, with wings extended; the 
natural position at rest is shown in Plate I, B ; and the wdng venation 
is illustrated in text figure 1. 

The following technical description is reprinted from Durrant 
and Beveridge : 

Antennae whitish fuscous ; basal joint with some darker fuscous scales. 
Head and Thorax very pale fuscous, sometimes whitish fuscous, or darker 
fuscous. Fore wings very pale fuscous, the veins more or less indicated by 
darker fuscous scaling, and with a tendency to suffusion over the whole wing, 
except along the dorsum which remains of the pale ground-color; in some 
specimens the darker markings are almost absent, in others there is a tendency 
to form two irregular transverse dark lines, one at the end of the cell, the 
other at about half the wing-length, with some dark shading toward the base ; 
a more or less distinct dark spot occurs on the margin at the end of each vein ; 
cilia pale fuscous, with some admixture of darker scales. Exp. ah 14-24 mm. 
Hind wings, $ fuscous ; $ shining whitish fuscous ; cilia with a slightly paler 
line at their base. Abdomen and Legs pale fuscous. 

Synonymy. 

Corcyra cephalonica Staint., Ragonot, Ent. Mo. Mag., v. 22, p. 22, 23, 18S5. 
Melissohlaptes (?) cephalonica Staint., Ent. Mo. Mag., v. 2, p. 172-173, 

18G6. 
Melissohlaptes transUneclla Rag.-Hamps., Mem. Lep., p. 491, pi. 45, fig. 

23 ; pi. 51, fig. 26, 1901. 
Tineopsis theohromae Dyar, Ins. Inscit. Mens., v. 1, no. 5, p. 59, 1913. 

THE EGG. 

PI. II. 

The eggs have a pearly luster, are variable in shape, and have at one end 
usually a decided nipple, somewhat like that of certain fruits. The eggs are 
sufficiently large to be readily seen without the aid of a lens, and resemble 
somewhat those of the Mediterranean flour moth (Ephestia kueJmiella Zell.). 
The exact dimensions have not been obtained. 

THE LARVA. 

PI. Ill, A. 

The larva when fully developed bears some resemblance to that of Plodia 
interptinctella. The sutures of the joints are somewhat more pronounced ; the 
general color varies from white to a dirty, slightly bluish gray with occasional 
faint greenish tints. This dirty appearance of the larvre is due to the dark 
material on which they feed and is especially evident in the immature stages. 
Larvae which have fed on rice are more nearly white than those which develop 
from cacao preparations. 



4 BULLETIN 783^ U. S. DEPARTME:N'T OF AGRICULTURE. 

The head, without the mandibles, is truncate anteriorly and siibtruncate 
posteriorly. The general color is rather dark honey-yellow, inclined to brown. 
The thoracic plate is pale honey -yellow, well divided at the suture and, while a 
little darker on the outer margin, is nearly uniform in color. The anal plate 
is very pale, scarcely darker than the joints. The three pairs of fore legs are 
rather long and prominent. The prolegs, with the anal leg^, are also prominent 
but shorter. Observed under a strong lens the spiracles and piliferous tubercles 
are minute but distinct, and the pubescence, although sparse and of fine texture, 
is rather long, some hairs being nearly as long as the width of the body. 

The average length when extended is about 13 mm. and the greatest width 
about 1.5 mm. 

THE PUPA. 

VI. Ill, B, C. 

In general appearance the pupa resembles that of other cereal-feeding moths. 
The general color is pale yellow. The form is robust, and the arrangement of 
the segments is well shown in Plate III, B and 0, the latter illustrating the 
ventral arrangement of the legs and wing pads. These latter extend nearly to 
the antepenultimate abdominal segment. The eyes, in fresh specimens, show 
merely as circular areas but when nearing transformation they become black. 
The antennal sheathes slightly overlap on the posterior margin. The best 
characters appear on the dorsum, the short median parallel elevated longi- 
tudinal lines evidently being characteristic, as the.v are nearly black and quite 
distinctly marked. The spiracles are small but distinct. The anal segment 
bears at the apex four processes, the anterior ones being in the nature of 
short spines. 

Naturally there is a difference in the proportions of the pupa of this species 
as in the adult, the length ^varying from 7..5 mm. to 9 mm. 

When about to transform the larva prepares a cocoon by joining 
together, by means of silken threads, a mass of the material on which 
it is feeding, as shown in Plate IV, A. An exposed cocoon is illus- 
trated in Plate lY, B. 

DISTRIBUTION. 

While Corcyra cephalonica is loiown to occur in portions of 
Europe, Asia, Africa, and southern and insular America, it is by no 
means truly cosmopolitan. Durrant and Beveridge (9)^ record the 
Mediterranean region, India and Ceylon, the Cocos Keeling Islands, 
Christmas Island, the Kei Islands, western Sudan, Nj^assaland, La 
Reunion, Para, Brazil, and Cuba and Grenada, West Indies. Rago- 
not (7) records Italy, the Ionian Islands, and the Seychelles. To 
this list may be added Porto Eico, Mexico, Hawaii, and Penn- 
sylvania. 

FOOD HABITS. 

According to the authors just mentioned the rice moth would ap- 
pear to be of eastern origin, introduced into Europe and elsewhere 
by the rice trade, and this is undoubtedly true. They further state 

1 Figures in parentheses refer to " Literature cited," p. 14. 



Bui. 783, U. S. Dept. of Agriculture. 



Plate I, 





The Rice Moth (Corcyra cephalonica). 

A , Mature moth; B, same in natural position at rest. Much enlarged. 



Bui. 783, U. S. Dept. of Agriculture. 



PLATE I I . 




Eggs of the Rice Moth. Highly Enlarged. 



Bui. 783, U. S. Dept. of Agriculture. 



Plate III. 





Stages of the Rice Moth. 

A , Larva; B, pupa, dorsal view; C, same, ventral view. Much enlarged. 



Bui. 783, U. S. Dept. of Agriculture. 



Plate IV. 




Cocoons of the Rice Moth. 

A , Exterior, showing grains of rice; B , cocoon exposed by removal of rice grains. Enlarged. 



Bui. 783, U. S. Dept. of Agriculture. 



Plate V. 





Work of the RrcE Moth. 

A, Mass of rice closely matted together by larvae; B, cacao beans similarly attacked. 



THE KICE MOTH, 



that it was thought to be especially attached to currants, that it is 
imported into England with Eangoon rice, which seems to be its nat- 
ural food, and that there is little doubt that anything that will suf- 
fice for the genus Ephestia will be equally nourishing to the pres- 
ent species. This insect was also obtained in tins of army biscuit, 
but no particulars are given as to its breeding habits beyond what 
has alread}^ been said. The larva has been observed in Paris in the 
grain of sesame {Sesammiv oHentale) from Sudan, West Africa. 

Plate IV and Plate V, A, illustrate the manner in which the 
cocoons of the rice moth are made by the larva in confining the 




'^^M- 



'^^' ■ 



Fig. 2. 



-Army biscuit showing lioles eaten by larviB of the rice moth and webbing by 
same. (After Durrant and Beveridge.) 



grains of rice by means of silken threads. Text figure 2 shows in- 
jury by the larvae to an army biscuit, and Plate V, B, injury to cacao 
beans. 

REPORTED INJURIES. 

One of the firms which experienced trouble from this pest stated 
that the raw cacao beans, when received in bags, are stored in rooms 
about 16 feet high, some of the bags being piled nearly to the ceiling 
and others about 8 feet high. Wlien the bags are disturbed the moths 
fly from between them and on examination numerous larvae and 
cocoons may be found in such locations. Cocoons occupied or empty 
may be observed in almost any crevice in the walls of the storerooms. 



6 BULLETIN 783, U. S, DEPARTMENT OF AGRICULTURE. 

Correspondents also note that the^ oldest cacao beans are, as a rule, 
the most heavily infested. 

May 6, 1914, 10 moths of this- species-^ were placed in a rearing jar 
with cacao beans as food. One moth was still alive on May 27, but 
was found dead the following day, having lived 21 days without food. 
According to Dyar the tongue is completely absent in this moth, so 
it is unable to feed. No evidence of insect attack could be noted 
through the glass jar when examined on July 9, but when some of the 
beans, which had become moldy on account of the moist weather dur- 
ing this period, were opened, a mature larva and a cocoon contain- 
ing a pupa were found. Attack was confined chiefly to beans that 
already had been injured more or less. 

March 8, 191G, Dr. Carl Michel, United States Public Health Serv- 
ice, San Juan, P. K.., furnished moths and pupae, the latter in webbed- 
up rice, and stated that the species infests warehouses in Porto Pico, 
that the eggs are laid in sacks of cereals, and that the developing larvae 
render the cereals unfit for human consumption. The merchants at 
San Juan claim that the rice is infested before it reaches that port 
and that nearly all of it is concentrated at Xew Orleans or Galveston 
for shipment. The claim is not made, however, although it is in- 
ferred, that the insect is shipped from the United States, but it 
seems more probable that the moth has been established in Porto Rico 
for a number of j^ears. Agents of the Bureau of Entomology spent 
much time from 1908 to 1916 iuA'estigating insects injurious to rice 
and other stored products from New Orleans and Galveston, but they 
did not observe this insect at these or other ports. It may have been 
introduced recentl}' through carelessness in vessels returning from 
Porto Pico containing foodstuffs on which it was able to subsist. On 
March 22 Dr. Michel sent additional specimens of larvae in infested 
rice. The larvae were all paler than were those reared from darker 
substances, such as chocolate and similar products, and as a result it 
was noted that the piliferoi,is tubercles were plainly visible, whereas 
in the darker forms they were scarcely noticeable. September 12, 
1916, numerous larvae and some pupae of this species were received in 
rice from the same source. The correspondent stated that some of 
the moths had been breeding continuously since the previous Feb- 
ruary, and that thej^ thrived at room temperatures. 

May 19, 1916, samples of rice infested by this species were again 
received, and on September 18 the Bureau of Chemistry reported 
that this specific shipment of rice was California grown, milled in 
San Francisco, and shipped via Panama Canal to New York City 
where it was held for about 30 days, and then reshipped to San Jaun, 
P. E., where upon its arrival the buyers rejected it because the 
market had declined, but not on account of " vermin," as the rice 
was apparently in sound condition. The rice was kept until October 



THE RICE MOTH, 7 

30, and in the meantime the rice moth and other pests developed and 
the rice was condemned by the United States Government. Finally, 
the rice was shipped to New Orleans to be reconditioned, and was 
put into a condition satisfactorj' to the Federal authorities. 

December 7 of that year, a chocolate firm in Pennsylvania, which 
previously had furnished specimens, wrote that the moths disappear 
with the arrival of cold weather and are not seen again until the 
following spring. During the late spring months and all summer 
they are in evidence. The greatest trouble is experienced from the 
laying of eggs by the moths on the finished chocolate and cocoa. The 
eggs hatch into larvae and the customer naturally objects to " wormy " 
goods. Attempts were being made to avoid this as much as possible 
by keeping finished materials covered. 

LIFE HISTORY. 

The complete life history of the rice moth has not been ascertained. 
The progress which might have been made with other insects in 
similar investigations was prevented in this case by the fact that 
seldom more than two generations were obtained in a single rearing 
jar of cocoa or related substances. When confined in large numbers 
the larvae, like others of similar habits, such as Ephestia, travel, evi- 
dently in an endeavor to secure a suitable location for transforma- 
tion to pupa?, to a greater extent than do the other species. This might 
explain the fact that the pupal cases or cocoons usually are found 
either on the outside of the bags at point of contact in the piles, or in 
the folds of the burlap sacks, which provide more or less shelter. In 
the rearing jars, although small pieces of cloth were inserted to form 
shelters for the pupae, the thick webbing spun by the larvae com- 
pletely covered the infested material, preventing the exit of the 
moths, which died without being able to reproduce. This fact is 
mentioned because it happened in the case of a half dozen rearing 
jars of large size (about 8 liters capacity). 

It has been ascertained, nevertheless, that the insect requires only 
a short time to develop from larva to adult, this period being de- 
dependent on temperature. The entire summer period for trans- 
formation from egg to egg is between 28 and 42 days, or from 4 to 6 
weeks, but this period would be prolonged considerably in cooler 
weather. 

Better results attended rearing experiments with this species in 
infested rice from Porto Rico. From a lot of moths which deposited 
eggs about May 26 a new generation of moths began to issue July 8, 
this period having been passed in 43 days, or approximately 6 weel^. 
The temperature ranged from 52° to 82° F., reaching the maximum 
only on a few occasions, and the average or mean temperature for 
the experiment was from 68° to 70° F. 



8 BULLETIN 783^ U. S. DEPAr.TMEXT OF AGRICULTURE. 

The question has been raised by importers and manufacturers as 
to whether or not it is possible to retard the development of the rice 
moth in order that control measures may be undertaken at desirable 
times. Wliile it was not possible to undertake any experiments 
along this line, it is known from analogy that development could be 
considerably retarded by cold storage. The egg period might be 
extended from the normal length of time, 3 to 10 days, to about a 
month ; the larval period to 6 months or more ; and the pupal period 
from the normal of from 5 to 14 days to 4 weeks or longer, making 
a possible total of about 8 months. 

While complete life-histor}^ data of this species would be desirable, 
what has been learned is sufficient to show that such life-history 
studies would not differ essentially from those of related species, 
such as the Mediterranean flour moth and the Indian-meal moth, 
and it has been developed that there is a practical certainty of four 
generations annually and a possibility of as many as six in high 
temperatures. 

ASSOCIATED INSECTS. 

The fig moth {Ephestia cautella^diV&.)., as previously stated, has 
been associated with this species in infested rice and cocoa products. 
In one rearing jar containing the rice moth breeding in cocoa, 
received June 18, 1915, the larvae of the latter were full grown on 
August 27. The jar was examined again on September 10 and appar- 
ently contained only the fig moth with its larva?. This latter had evi- 
dently " run out " the former, its larvae perhaps feeding on the larvae 
and pupae of the rice moth, which in nature is not an unusual occur- 
rence.^ Some, however, remained, and in a few days the rice moth 
reappeared. In this particular rearing cage the fig moth must have 
deposited her eggs through the mesh covering the jar, although this 
was decidedly thick and closely woven. Fig-moth females have been 
known to do this in previous instances. 

The Indian-meal moth {Plodla interi-)unctclla Hbn.) developed in- 
great numbers in a lot of chocolate in which the rice moth had been 
reproducing abundantly, completely devouring the edible material 
and then perishing. 

It may be noted that when closely confined with edible material 
the three moths mentioned, in common with others which feed upon 
stored products, frequently perish because of the compact webbing 
which prevents escape and the lack of moisture which produces 
excessive drying of their food supply, curtailing the longer repro- 
duction period of the species. 

1 The larvae of the cabbage woiiii (Pontia rapae L.) have been noted feeding on the 
'^ggs of the cabbage looper ( Autotjropha hriif:sicae Riley). The corn earworm (Chloridea 
oosoleta Fab.) is also well known to be cannibalistic. 



THE RICE MOTH. 9 

Some forms of beetles, however, are able to continue feeding in the 
absence of moisture until the supply of food is exhausted. 

The saw-toothed grain beetle (Sllvanus surinamensis L.) has been 
found in several instances associated with the rice moth. Obviously 
it plays the same role with this species as with other moths — a scav- 
enger, although a decidedly noxious pest. 

The rust-red flour beetle {TrlholiuTn ferrugineum. Fab.) has been 
observed in the same situations as the saw-toothed grain beetle. 

The lesser grain-borer {RhizopertJui domimca Fab.) was received 
in rice from Porto Rico associated with stages of the rice moth. 

The Siamese gi'ain beetle {Lophocateres pwsilla Oliv.) was ob- 
served breeding in numbers in a sample of Porto Rican rice some 
time after receipt, showing that the immature stages were present at 
an earlier date. 

The rice weevil {Calandra oryza L.) was present in small nmnbers 
in most of the samples inspected. It was noticeable in broken rice 
that the beetles which developed in such small quarters were not as 
large as those which are found in soft kernels of corn and wheat. 
The color of the beetles taken in broken rice was brighter and they 
had the appearance of being a distinct species. 

HISTORY AND LITERATURE. 

Wliile the rice moth probably has been present in Europe for 
man}^ j^ears, it was not until 18G6 that it was discovered in York, 
England, and described as a new species by Stainton (1). It was 
found in imported dried " currants " {Pmsulae corintMcae) , called 
" Corinthian currants," but in reality a well-known species of grape. 
In 1875 Barrett (2) mentioned the occurrence of this species in fruit 
warehouses in London, together with other insects of similar habits. 
In 1885 (3), 1893 (4), and 1901 (7) Ragonot wrote, in technical 
articles, in regard to the classification and characters of this species, 
without reference to its injurious habits. In 1895 Me3^rick (5) gave 
a brief technical description of the adult, stating that the larva 
occurs in dried " currants." In 1897 (6) the author mentioned this 
species in a list of insects likely to occur in this country in dried 
fruit. In 1909-10 Fletcher (8) recorded the species as occurring in 
rice from the West Indies. 

In 1913 Durrant and Beveridge (9) wrote the most extensive ac- 
count of the insect which had appeared to that date, referring espe- 
cially to its occurrence in army biscuits and the temperature which 
would destroy this and other species of related habits. An article 
dealing with this insect, by Otto H. Swezey (10), appeared the same 
year. 

In 1908 the rice moth came to the attention of Mr. Jacob Kotinsky 
of the Bureau of Entomology, at that time in Hawaii, who found it 



10 BULLETIISr 783, U. S. DEPARTMENT OF AGRICULTURE. 

breeding in a feed warehouse in Honolulu in July. On July 10. 1909, 
it was captured at Kaena Point by Mr. Swezey. The latter part of 
the same month moths were found emerging from a package of 
cracked wheat obtained from a Honolulu grocen,'. Mr. Swezey 
expressed the opinion that although the species is a European moth 
apparently not recorded at that time in the United States, it certainly 
must have reached Honolulu from the United States. 

The habits of the moth are well described by Barrett (2). He 
states that when disturbed in flight, unlike Ephestia and Plodia, it 
darts down in a zigzag and almost immediately comes to rest. To- 
ward evening the males run about, quivering their wings in a peculiar 
manner. The moth shows considerable skill in selecting for a resting 
place the projections of rough beams, to which, owing to its rough, 
blunt head and closely folded wrings, it bears so close a resemblance 
that Barrett states he has taken specimens between his fingers before 
he could satisfy himself that they were not projecting splinters. 
This can be readily appreciated by reference to Plate I, B, which 
shows the moth at rest. The moth is peculiarly sluggish, even more 
so than those of the other genera. Barrett writes of this and of a 
related species (Ephestia) that they were being replenished con- 
stantly from imported dried fruits, since every cargo of fruit 
swarmed with the larvse, some of which died from change of climate 
and other causes, but many of which came to maturity. He states 
that it is obvious that places in which old " currants " have been 
stored are the most potent sources of infestation, the new fruit coming 
into harbor during the month of September when the moths are al- 
ready plentiful. He believed that the different species occurred in 
about equal numbers and was certain that they had formed a settle- 
ment from which it would be no easy task to expel them. 

CONTROL MEASURES. 

Warehouses and other structures in which the rice moth has be- 
come established should be cleansed thoroughly. Any bags which 
contain or have contained infested rice or other cereal, cacao beans, 
cocoa or similar material, or dried fruits should be fumigated; all 
corners, cracks, and crevices which may harbor the insect should be 
brushed out; and all refuse promptly destroyed by burning. The 
walls and floors then ma}" be washed down with a soluble creosote 
disinfectant, or a solution of common salt. The brushes used should 
be stiff and strong, and every point should be reached so as to make 
the compartment perfectly clean. 

The machinery also should be cleaned thoroughly and the entire 
plant fumigated with hydrocyanic-acid gas. In small plants either 
carbon disulphid or sulphur dioxid may be employed for fumigation, 



THE RICE MOTH. 11 

but if the buildings are so constructed that heat of 120° to 130° F. 
may be applied for several hours, the same result will be accom- 
plished. 

Secondhand bags should not be used without first disinfecting 
them and bags previously used for the transportation of cacao beans 
or other food materials which the rice moth is known to attack should 
be examined for the presence of the insect in its various stages. Wlien 
insects are found it is best to establish a quarantine bin, room, or 
fumigator in which the infested bags may be thoroughl}^ baked or 
fumigated before they are taken into the main building. If it is 
desired to fumigate a compartment containing bags filled with cacao 
beans, rice, or similar material the bags should first be brushed off 
carefully and the tiers of bags so separated as to leave air space be- 
tween in order that the gas may penetrate the contents more readily. 
Even after fumigation there is always a possibility that a small per- 
centage of the insects may remain and revive. 

DESTRUCTION BY HEAT. 

Treatment of insect-infested stored products by heat is by no 
means a new remedy, but large-scale work with this method had not 
been conducted to any extent until about 10 years prior to the time 
of writing. This method appears to have been first successfully 
used in the control of mill pests at that time by the Kansas Agri- 
cultural Experiment Station, for the control of both the Mediter- 
ranean flour moth and the Indian-meal moth. Soon thereafter Mr. 
C. H. Popenoe, of the Bureau of Entomology, conducted experiments 
in Virginia, under the writer's direction, which were quite successful 
against both of these pests. 

The heat method is equallj^^ applicable for the rice moth, although 
it is valuable only for mills or other structures heated or operated by 
steam, since it presupposes the installation of necessary heating pipes 
and radiators. The temperature required, from 120° to 130° F., 
can be obtained readily in a mill provided with sufficient radiation 
surface to maintain a winter temperature of 75°. A warm, quiet 
day should be selected for best results, and the temperature after 
being reached should be maintained for 8 hours or more in order to 
insure penetration. Should additional radiation surface be required, 
it may be provided hj the installation of temporary supplementary 
coils of 1^-inch pipe, which will operate to best advantage if placed 
near the floor. In mills where a complete installation is required, 
radiators should be calculated on a basis of 1 foot of heating surface 
(2^ linear feet of l|-inch pipe) to from 50 to 100 cubic feet of space, 
depending on the construction of the building and the situation of 
the coils. The maximum figure should be applied to the lower floors. 



12 BULLETII^ 783, U. S. DEPARTMENT OE AGRICULTURE. 

A steam pressure of from 75 to 100 jiounds may be employed advan- 
tageously. Since bags of compact material are heated to the center 
with difficulty, so far as possible they should be separated before 
treatment to facilitate uniform heating, for insects and their larvse 
become more active upon the application of the heat and may work 
their way to the center of the bags in their efforts to escape it. 

Better results may be obtained by providing the radiators with 
water traps or vents. 

Rice and cacao beans should not be exposed to a temperature above 
130° F. for more than one hour, as excessive splitting takes place in 
rice, especially if bleached, and, owing to the excessively oily nature 
of cacao beans, they may become rancid. 

Germination in the case of some seeds, such as peanuts, is not af- 
fected even by an exposure of six hours to a temperature as high as 
140° F., but it is best to be on the safe side in the treatment of com- 
modities affected by this moth until we have had more experience 
along this line. It should be added that a temperature of 140° F. is 
fatal to most forms of insect life in a short time — larvae, pupae, and 
adults. The Indian-meal moth, it has been learned b}^ experiment in 
the Bureau of Entomolog}% dies m less than half an hour when so 
exposed. 

FUMIGATION METHODS. 

HYDROCYANIC-ACID GAS. 

For the fmnigation of buildings and other structures inhabited by 
the rice moth, the hydrocA'anic-acid gas process is the most useful. 
Indeed, it is now the standard remedy for practicallj' all insects 
affecting stored products. It has been in use for this purpose for 
about 20 years and most progressive millers are familiar with the 
method of application. Information in regard to hydrocyanic-acid 
gas fumigation has been furnished by the Bureau of Entomology in 
various bulletins and other publications. In the earlier ones the use 
of cyanid of potash or potassium cyanid was advised, but owing to 
conditions brought about by the war it is now impossible to secure 
this chemical, and as a result cj^anid of soda or sodium cyanid is 
being used, and while somewhat expensive, is much cheaper than the 
corresponding potash salt. The formula is as follows : 

Sodium cyanid ■ avoirdupois ounce 1 

Sulphuric acid fluid ounces — IJ 

Water do 3 

Information in regard to this method is furnished in Farmers' 
Bulletin G99, " Hydrocyanic-acid Gas Against Household Insects." 
While this, as the title shows, is especially for dwellings, the methods 
advised can be adapted readily to mills and storehouses. 



THE EICE MOTH. 13 

Hydrocyanic-acid gas, it must be stated, is the most poisonous 
substance in common use, but it is still employed very extensively 
in fumigating mills and dwellings, and if the directions in the 
bulletins cited are carefully carried out there is really no danger to 
human beings. 

CABBON DISULPHID. 

Before the general adoption of hydrocyanic-acid gas as a means 
of fumigating buildings, carbon disulphid was considered a standard, 
and it is still of value, particularly on a small scale, as a substitute 
for hydrocyanic- acid gas. It is extremely inflammable, however, 
which has led to its abandonment in many localities. Directions for 
its use are given in Farmers' Bulletin 799 ^ " Carbon Disulphid as an 
Insecticide." 

SUMMARY. 

1. The rice moth {Corcyra cephalonica Staint.) has been known 
to occur in the United States only since 1911, and was not identified 
until 191G. 

2. Its origin is unknown, but it has been introduced at many points 
in other continents and is as yet not strictly cosmopolitan. It has 
been found commonly in England, where it was introduced in rice, 
chiefly from India and Burma, and also in dried fruits. 

3. Its habit of feeding on cacao beans is probably an acquired one. 
Evidently it is inclined to be omnivorous, since it breeds in rice, 
dried fruits, the various products of cacao, such as cocoa, cacao 
shells, and sweetened and uns^'eetened chocolate, ship biscuits, and 
sesame seeds. It displays, however, no partiality for any of these 
food substances. 

4. Its complete life history has not been traced, but, like other 
indoor species, it reproduces nearly the year around under average 
conditions. In the United States infestations appear to die clown 
from time to time, but are stimulated through new shipments of 
cacao beans from South America and Central America. 

5. It produces copious and dense external webbing to which food 
materials, such as rice, cocoa, and other matter, strongly adhere. 
In this respect its work and injury resemble those of the flg moth 
{Eyhestia cautelJa Walk.) and related species, and the Indian-meal 
moth {Plodia interpuncteIJa Hbn.). 

(6) While it has been recognized only from western Pennsylvania 
and Porto Eico, it occurs without doubt at other points, and dealers 
in rice, chocolate, and similar imported dry edibles should keep a 

1 The Farmers' Bulletins mentioned may be obtained free on application to the Division 
of Publications, United States Department of Agriculture. 



14 BULLETIN 783, U. S. DEPARTMENT OP AGRICULTURE. 

lookout for the species to prevent it from gaining entrance and be- 
coming established in large warehouses and similar plants. 

7. It will undoubtedly increase in injuriousness in time unless 
proper measures are taken to stamp it out by thorough treatment. 

LITERATURE CITED. 

(1) Stainton, H. T. 

1866. Description of a new species of the family Galleridae. In Ent. 
Mo. Mag., V. 2, 1866, p. 172-173. 
Original description as Melissohlaptes (?) cephaloiiica n. sp., from York, 
Eng., from dried " currants " (imported). 

(2) Barrett, C. G. 

1875. On the species of Ephestia occiirring in Great Britain. In Ent. 
Mo. Mag., V. 11, p. 269. 
Page 272 : In fruit warehouses in dried " currants." Notes on habits. 

(3) Ragonot, E. L. 

1885. Revision of the British species of Phycitidse and Galleridse. In 
Ent. Mo. Mag., v. 22, 1885-6, p. 17-32. 
Pages 22—23 : Remarks ; placed in genus Corcyra from the country of its 
supposed origin. 

(4) . 

1893. Monographie des Galleriinae et Phycitinae. In Romanoff, N. M., 
Memoires sur les L§pidopteres. t. 7. Saint Petersbourg. 
Illustrations : Head of female, pi. 1, fig. 34 ; venation, pi. 3, flg. 18. 

(5) Meyrick, E. 

1895. A liandbook of British Lepidoptera. 813 p., illus. London. 
Page 384 : Technical description of the moth and brief notes. 

(6) Chittenden, F. H. 

1S07. Some little-known insects affecting stored vegetable products. 
U. S. Dept. Agr. Div. Ent. Bui. 8, n. s. 45 p., 10 figs. 
Page 10 : Mere mention as a species likely to be found in this country in 
dried fruit. 

(7) Ragonot, E. L. 

1901. Monogi-aphie des Galleriinae. In Romanoff, N. M., Memoires sur 
les Lepidopteres. t. 8, p. 421-507. Saint Petersbourg. 

Pages 491-493, pi. 45, fig. 23, and pi. 51, flg. 26 : Definition of genus 
Corcyra, description of ceplialonica and translineeUa (=synonym) and 
plate of each. 

(8) Fletcher, T. B. 

1909-10. Lepidoptera, exclusive of the Tortricidre and Tineidfe, witli 
some remarks on their distribution and means of dispersal 
amongst the islands of the Indian Ocean. In Trans. Linn. Soc, 
s. 2, V. 13, Zoology, p. 265-323, pi. 17. 
Pages 296 and 316 : Recorded from West Indies ; mention as common In 
rice stores. 

(9) Durrant, J. H., and Beveridge, W. W. O. 

1913. A preliminarj' report of the temperature reached in army biscuits 
during baking, especially with reference to the destruction of 
the imported floui'-moth, Ephestia kiihniella Zeller. In Jour. 
Roy. Army Med. Corps, v. 20, no. 6, p. 615-634, 7 pi. 

Pages 633—634 : Occurrence in army biscuit, description, bibliography, 
and distribution ; illustrations of the moth, larva, and injury. 



THE RICE MOTH. 15 

(10) SwEZEY, Otto H. 

1913. Notes on two .galleriid.s. In Proe. Hawaiian Entom. Soc, Hono- 
lulu, Hawaii, v. 2, p. 211-212. 

Pago 212 : Occurrence in Hawaii in 1908-1909 in a feed house and in 
cracked wheat. 

(11) Dyae, H. G. 

1913. A galleriine feeding in cacao pods. In Ins. Inscit. Mens., v. 1, no. 5, 
p. 59. 

Characterization of Tineopsis n. g., and description of T. theoiromae n. sp., 
as follows : " Dark gray ; fore wing without markings. Hind wing 
paler, silky gray. The head is heavily tufted and with the narrow, 
pointed wings gives the insect the aspect of a Tineid. Expanse, 13-15 



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